Equine Herpes Virus (EHV) is a virus that can cause mild respiratory disease in young horses. As with the flu virus this can then lead to further complications such as pneumonia. EHV can also cause the more serious problem of abortion in pregnant mares and it is therefore recommended that breeding animals (stallions and broodmares) should be vaccinated against EHV. Rarely, EHV can also cause paralysis in horses and can be fatal. Vaccination against EHV reduces the chance of becoming infected, and reduces the concentration of virus in the local environment making infection of other horses less likely.